HMP also known as the Pentose phosphate pathway. Consists of two irreversible oxidative rxs followed by a series of reversible Quantitative Importance of the Pentose Phosphate Pathway Determined by Incorporation of 13C from [2 13C] and [3 13C]Glucose into TCA Cycle Intermediates and Neurotransmitter Amino Acids in Functionally Intact Neurons Eva M F biochemistry Why is the Pentose Phosphate Pathway so active in erythrocytes? Biology Stack Exchange Glucose metabolism begins with its transport into cells via GLUT transporters, where it is phosphorylated to glucose 6 phosphate (Glucose 6 P). This molecule can enter various pathways, including the pentose phosphate pathway or hexosamine biosynthesis.